Polyamide compositions

Abstract

The invention relates to compositions based on polyamide blends and additives, to the use of these compositions in moulding compositions for production of products having short-term heat distortion resistance, and to a process for producing polyamide-based products having short-term heat distortion resistance, especially for electrics or electronics applications.

What is claimed is: 
     
         1 . Compositions comprising:
 a) 15% to 90% by weight of nylon-6,6,   b) 3% to 30% by weight of at least one thermoplastic polyamide from the group of nylon-4,6 and/or the semiaromatic copolyamides containing terephthalic acid as monomer unit and having a melting point in the range from 270° C. to 330° C., where the proportion of component b) or components b), based on the sum total of all the thermoplastic polymers present in the composition, is 5% to 40% by weight,   c) 5% to 70% by weight of glass fibres, and   d) 0.01% to 3% by weight of at least one thermal stabilizer, where the sum total of all the percentages by weight is always 100.   
     
     
         2 . Compositions according to  claim 1 , wherein they comprise, in addition to components a), b), c) and d), also e) 0.01% to 5% by weight of dipentaerythritol and/or tripentaerythritol, in which case the levels of the other components are reduced to such an extent that the sum total of all the percentages by weight is always 100. 
     
     
         3 . Compositions according to  claim 2 , wherein they comprise, in addition to components a), b), c), d) and e) or instead of e), also f) 1% to 55% by weight of at least one flame retardant, in which case the levels of the other components are reduced to such an extent that the sum total of all the percentages by weight is always 100. 
     
     
         4 . Compositions according to  claim 3 , wherein they comprise, in addition to components a) to f) or instead of components e) and/or f), also g) 0.01% to 10% by weight of at least one additive having two epoxy groups per molecule, in which case the levels of the other components are reduced to such an extent that the sum total of all the percentages by weight is 100. 
     
     
         5 . Compositions according to  claim 4 , wherein they comprise, in addition to components a) to g) or instead of components e) and/or f) and/or g), also h) 0.01% to 20% by weight of at least one additive other than components c) to g), in which case the levels of the other components are reduced to such an extent that the sum total of all the percentages by weight is 100. 
     
     
         6 . Compositions according to  claim 1 , wherein the thermal stabilizers are selected from the group of the sterically hindered phenols, these being compounds having phenolic structure and having at least one sterically demanding group on the phenolic ring, sterically demanding groups being tert-butyl groups, isopropyl groups and aryl groups substituted by sterically demanding groups. 
     
     
         7 . Compositions according to  claim 6 , wherein the thermal stabilizers contain at least one structure of the formula (II) 
       
         
           
           
               
               
           
         
       
       in which R 1  and R 2  are each an alkyl group, a substituted alkyl group or a substituted triazole group, where the R 1  and R 2  radicals may be the same or different and R 3  is an alkyl group, a substituted alkyl group, an alkoxy group or a substituted amino group. 
     
     
         8 . Compositions according to  claim 6 , where the thermal stabilizers used are sterically hindered phenols derived from substituted benzenecarboxylic acids. 
     
     
         9 . Compositions according to  claim 8 , where the thermal stabilizer is from substituted benzenepropionic acids. 
     
     
         10 . Compositions according to  claim 9 , where the thermal stabilizer is a compound of the formula (III) 
       
         
           
           
               
               
           
         
       
       where R, R 5 , R 7  and R 8  are each independently C 1 -C 8 -alkyl groups which may themselves be substituted (at least one of these is a sterically demanding group) and R 6  is a divalent aliphatic radical having 1 to 10 carbon atoms, which may also have C—O bonds in the main chain. 
     
     
         11 . Compositions according to  claim 8 , wherein the thermal stabilizers are selected from the group of 2,2′-methylenebis(4-methyl-6-tert-butylphenol), 1,6-hexanediyl bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], pentaerythrityl tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], distearyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, 2,6,7-trioxa-1-phosphabicyclo[2.2.2]oct-4-ylmethyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, 3,5-di-tert-butyl-4-hydroxyphenyl-3,5-distearylthiotriazylamine, 2-(2′-hydroxy-3′-hydroxy-3′,5′-di-tert-butylphenyl)-5-chlorobenzotriazole, 2,6-di-tert-butyl-4-hydroxymethylphenol, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 4,4′-methylenebis(2,6-di-tert-butylphenol), 3,5-di-tert-butyl-4-hydroxybenzyldimethylamine. 
     
     
         12 . Compositions according to  claim 6 , wherein the thermal stabilizers are selected from the group of 2,2′-methylenebis(4-methyl-6-tert-butylphenol), 1,6-hexanediyl bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], pentaerythrityl tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and N,N′-hexamethylenebis-3,5-di-tert-butyl-4-hydroxyhydrocinnamide. 
     
     
         13 . Compositions according to  claim 5 , characterized in that the pigment titanium dioxide is used as additive. 
     
     
         14 . Products obtainable by extrusion or injection moulding of moulding compositions comprising the compositions according to  claim 1 . 
     
     
         15 . Products according to  claim 14 , characterized in that they are products having short-term heat distortion resistance for the electrics or electronics industry. 
     
     
         16 . Process for producing products having short-term heat distortion resistance, characterized in that compositions according to  claim 1  are processed to give moulding compositions and these are subjected to an injection moulding or extrusion operation.